Page History

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1. There are serious problems with using multicast technologies on NCSA's production resource subnets.
2. We do not require the full generality of JavaSpaces with respect to serializable classes; our service accepts an open-ended (i.e., basically untyped) wrapper object containing a serialized xml blob corresponding to the (which usually, but not necessarily, will implement ncsa.tools.common.types.Configuration object UserFacing) as its payload element.
3. We do not require the full peer-to-peer capabilities offered by Jini.

API

Service WSDL

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ITupleSpace

public interface IConfigurationSpaceITupleSpace
{
	Integer write( String entryXML ) throws Throwable;
        Integer[] writeB( String[] entryXML ) throws Throwable;
	String[] read( String matchXML, int max ) throws Throwable;
	String[] take( String matchXML, int max, long timeout ) throws Throwable;
	String[] takeNB( String matchXML, int max ) throws Throwable;
}

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• write takes a serialized string representing the ncsa.service.vizier.tspace.ConfigurationEntryTspaceEntry object (see below); returns the entry id.
• writeB is a batch method which does the same thing as write on multiple entries; returns array of ids corresponding to each entry.
• read and take are batch methods, both requiring a serialized string representing the ncsa.service.vizier.tspace.ConfigurationMatchRequestTspaceMatchRequest object (see below), along with an integer indicating the maximum number of entries to return (default is 10; it is advisable not to set this number too high, as Axis will have trouble managing extremely large SOAP packets); the array returned contains serialized ncsa.service.vizier.tspace.ConfigurationEntryTspaceEntry objects.
• take also requires a timeout (if set to t <= 0, the non-blocking method is called), whereas takeNB will return immediately subsequent to issuing the request against the data store.
  • takeNB can return null if no entries satisfy the request constraints.
  • take will not return null unless timeout <= 0.
  • take may return an empty array (length 0) if its timeout has been exceeded.

ncsa.service.vizier.tspace.

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TspaceEntry

The object stored in the service's data store and which can be retrieved through the read or take ports. A fuller description of the object is found on the ncsa.tools.ogrscript.tspace page.

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